@@ -11,13 +11,14 @@ _sf_{{ COMMAND_NAME }}() {
 local sf_cmd="${COMP_WORDS[0]}"
 
 # for an alias, get the real script behind it
-if [[ $(type -t $sf_cmd) == "alias" ]]; then
+sf_cmd_type=$(type -t $sf_cmd)
+if [[ $sf_cmd_type == "alias" ]]; then
 sf_cmd=$(alias $sf_cmd | sed -E "s/alias $sf_cmd='(.*)'/\1/")
-else
+elif [[ $sf_cmd_type == "file" ]]; then
 sf_cmd=$(type -p $sf_cmd)
 fi
 
-if [ ! -x "$sf_cmd" ]; then
+if [[ $sf_cmd_type != "function" && ! -x $sf_cmd ]]; then
 return 1
 fi